Instruction manual
CI-ControlWaveLP Installation / 2-11
An illustration of the CPU Module’s male 9-pin D-type connectors is provided in Figure 2-4.
Table 2-4 provides the connector pin assignments for ports 1 through 5.
Note: The following facts regarding ControlWaveLP RS-232 serial communications ports
should be observed when constructing communications cables:
• DCD must be high to transmit
• CTS must be high to transmit
• When port is set for full-duplex operation - RTS is always ON
• DTR is always high (when port is active)
• When port is set for half-duplex operation - CTS must go low after RTS goes low
Table 2-4 - Communication Port Connector Pin Assignments
Pin
#
Signal
RS-232
Signal
RS-485
Description :
RS-232 signals
Description:
RS485 signals
1 DCD CTS+ Data Carrier Detect (Input) Clear to Send + Input
2 RXD RXD- Receive Data (Input) Receive Data - Input
3 TXD TXD- Transmit Data (Output) Transmit Data - Output
4 DTR TXD+ Data Terminal Ready (Output) Transmit Data + Output
5 GND GND Signal/Power Ground Signal/Power Ground
6 DSR RXD+ Data Set Ready (Input) Receive Data + Input
7 RTS RTS- Request to Send (Output) Request to Send - Output
8 CTS CTS- Clear to Send (Input) Clear to Send - Input
9 RI RTS+ Ring Indicator (Input) Request to Send +
Output
Note: RS-485 Signals in Table 2-4 are only available on COM3.
RS-485 Ports
ControlWaveLP can use COM3 (configured for RS-485 operation) for local network
communications to multiple nodes up to 4000 feet away. Since this interface is intended for
network communications, Table 2-5 provides the appropriate connections for wiring the
master, 1st slave, and nth slave. Essentially, the master and the first slave transmit and
receive data on opposite lines; all slaves (from the first to the "nth") are paralleled (daisy
chained) across the same lines. The master node should be wired to one end of the RS-485
cable run. A 24-gauge paired conductor cable, such as Belden 9843 should be used. Note: A
full-duplex RS-485 network consisting of two ControlWaveLP nodes will not support any
other nodes, i.e., an RS-485 full-duplex network consisting of multiple nodes, will support
only one ControlWaveLP node.
Table 2-5 - RS-485 Network Connections (Pins 1, 7, 8 & 9 of connector are unused)
From
Master
To 1st
Slave
To nth
Slave
4 TXD+ 6 RXD+ 6 RXD+
3 TXD- 2 RXD- 2 RXD-
6 RXD+ 4 TXD+ 4 TXD+
2 RXD- 3 TXD- 3 TXD-
5 ISOGND 5 ISOGND 5 ISOGND
To ensure that the “Receive Data” lines are in a proper state during inactive transmission
periods, certain bias voltage levels must be maintained at the master and most distant
slave units. This is accomplished by configuring Switch SW1 (at these locations) so that the
100-ohm termination resistors are installed (see Table 2-6).